1. Technical Field
This disclosure relates to a light emitting display and a method for fabricating the same, and more particularly, to a light emitting display including a pattern useful for analyzing causes for defects in a thin film formed on a substrate, and a method for fabricating the same.
2. Discussion of Related Art
Organic light emitting displays, which have been widely used, have relatively simple structures. An organic light emitting display is also called an organic electroluminescence display device, which is an emissive display using an organic film layer as an emission layer. Unlike a liquid crystal display, a back light is not required, thereby reducing thickness and weight. Accordingly, organic light emitting displays have been actively developed as display panels for portable information terminals such as mobile computers, portable telephones, portable game devices, or electronic books.
In determining the causes of defects associated with driving the organic light emitting display and/or analyzing the characteristics of a device, many types of signals provided thereto are measured. Such signals are typically measured using a measuring tip. In a typical organic light emitting display, of the electrodes to which signals are provided, only the cathodes are exposed. The remaining electrodes, that is, the gate electrodes, source/drain electrodes, and anodes are covered by an insulating layer. Accordingly, to probe signals provided to the gate electrode, the source/drain electrodes, and the anode using a measuring tip, the insulating layer formed thereover is decapped to expose at least one of the electrodes.
However, in the signal measuring method as described above, thin films formed on the substrate are removed. During the removal of a thin film, a part of the thin film is damaged, so that it is difficult to determine the electrical characteristics of the thin film.
In another method for measuring signals of a thin film transistor formed in a pixel region, a test pattern is formed in a non-pixel region. Prior to encapsulating a substrate on which the thin film transistor is formed, defects in the thin film transistor are tested based on the test pattern.
However, the test pattern provides only a result as to whether or not the thin film transistor formed on the substrate has electrical characteristics different from desired electrical characteristics. It is difficult to determine the fundamental causes as to which of the thin films formed on the substrate causes a defect and what defects occur in the thin film.